Preparation of coffee.



deprive coffee beans of cafi'ein, without detracted with a solvent of caffein, preferably IINITED STATES PATEN @EEICE.

JOHANN FRIEDRICH MEYER, JR., LUDWIG ROSELIUS, AND KARL HEINRICH WIMMER, OF BREMEN, GERMANY, ASSIGNORS TO THE KAFFEE-HANDELS-AKTIENGESELLSOHAFT, OF

BREMEN, GERMANY.

To all whom it may concern:

Be it known that we, JOHANN FRIEDRICH MEYER, Jr., LUDWIG RosELIUs, and KARL l HEINRICH WIMMER, subjects of the German Emperor, residing at Bremen, Germany, have invented certain new and useful Improvements Relating to the Preparation or Treatment of Coffee, of which the following is a specification.

The present invention has for its object, to

stroying their other valuable properties. Numerous attempts made for this purpose have been unsuccessful, and especially the treatment of the beans with volatile solvents for caffein has producedunsatisfactory results. The reason for failure seems to have been in the cellular tissue or organic structure of the coffee beans, which renders a suf ficient penetration of the solvent almost im possible. Moreover, the caffein is contained in the beans in the shape of salts, which are hardly soluble at all in the volatile solvents. Finally there is the defect, that after pro longed treatment of the beans with the solvent it is exceedingly difficult to remove the solvent completely from the cells, even if the solvent had penetrated only'into the outer cellular layers of the beans.

According to the present invention the coffee beans are first subjected to a prelimi nary treatment which causes the beans to swell and loosens the structure or cellular tissue of the same, preferably by exposing them to dry steam of about 1%2 atmospheres in a closed receptacle. Subsequently gases or vapors having an acid or alkaline reaction are introduced into the apparatus, in order to decompose the salts of caifein. Ammonia, sulfurous acid, hydro-chloric acid andsimilar chemicals have been found specially suitable for this purpose. The caffein liberated by this treatment can be extracted more easily than its salts, and in case minute quantities of caifein have remained in the beans after the extraction, they are. volatilized by the subsequent roasting, because at the temperature of roasting coffee caffcin in its free state is ca able of sublimation, although this is not t e ease with its salts.

The beans treated as described are ex- Specification of Letters Patent.

Application filed May 4, 1906. Serial No. 315,180.

one which dissolves" only the latter, but as PREPARATION OF COFFEE.

Patented Sept. 1, 1908.

REISSUIEBD little as possible of the other constituents of the beans. We have found that benzene (also called benzol) is eminently suitable for this purpose, because an extract made With f it leaves on evaporation almost pure caffein. In using other solvents, such as alcohol or chloroform, it would be necessary, to restore to the coffee-beans the extract, which has been relieved of caifein. Instead of a single solvent, such as benzene, mixtures of volatile solvents, may, of course, be employed for extracting the coffee beans.

The extraction of caifein is very energetic and leaves only minute traces undissolved, while the solvent action of the mixture for other constituents of coffee is comparatively weak. The boiling point of the mixture is lower than that of the individual components, and the extraction therefore takes place at a lower tem )erature.

It is useful to subject t 1e coffee, after extraction, to the influence of dry steam at a pressure of about latmospheres, while keeping the beans continually in motion by stirring, or by causing the apparatus to revolve. An agitation of the beans is useful also during the extraction. In case traces of the extracting liquid remain in the beans in spite of this treatment with steam, these traces may be removed by subjecting the beans alternately to steam of different pressures, or alternately to pressure and vacuum. This treatment also serves to expel the traces of furfurol contained in the coffee, and to relieve the coffee of this constituent, which recent investigations have shown to be injurious.

Example. 100 kilograms of coffee beans are placed in a cylinder with a double jacket, the cylinder is heated indirectly by steam, in order to avoid as much as possible the condensation of the dry steam to be introduced. Subsequently, after the cylinder has been hermeticallyclosed, steam is introduced until the pressure has risen to about 1%2 atmospheres. This pressure is allowed to act for about half an hour, after which gaseous ammonia is admitted. When the space is filled with this gas, benzene (or a mixture of benzene and alcohol) is admitted and heated, the immediate eflect of this being, that the escaping benzene vapors will carry with them any moisture that may be present and also the excess of ammonia.

The heating is then continued for about 2 to 3 hours, and the benzene vapors thereby produced are condensed in the known manner and re-conducted into the apparatus. If necessary, the preliminary treatment (mentioned at the beginning of this specification) is repeated.

When the extraction is completed, the last remnant of the solvent mixture is removed from the beans, by admitting to the extractor dry steam, until a pressure of about 1% atmospheres has been'established, which is maintained for about" 1 hour while conducting steam through the-contents and keeping the ap aratus in a rotary motion.

at we claim is z 1. The process for removing cafiein from green cofi'ee beans,- which consists in first treating the green coffee beans with dry steam in order to loosen the cellular structure, then treating them with gaseous chemicals adapted to liberate the cafiein from its salts, then extracting the cafiein with a volatile solvent and finally subjecting the ex tracted beans to a current of dry steam, substantially as described.

2. The process for removing caffein from green cofiee beans, which consists in first treating the green cofiee beans with dry steam in order to loosen the molecular structure, then treating them with gaseous chemicals adapted to liberate the cafieinfree from its salts, then extractin the caffein with a volatile solvent and final y subjecting the extracted beans to currents of dry steam at different pressures, substantially as described.

3. The process for removing cafiein from green coffee beans, which consists in first treating the green coflc'eebeans with dry steam in order to loosen the molecular structure, then treatin them with gaseous chemicals adapted to 1i erate the cafiein from its salts, then extracting the cafiein with a volatile solvent and finally subjectingthe extracted beans to a current of dry steam, while keepgreen coffee beans,

ing the beans in motion, substantially as described.

4. The process for removing cafiein from green coffee beans, which consists in first treating the green cofiee beans with dry steam and then with gases or vapors having an acid or alkaline reaction, subsequently extractmg ing them with a current of dry steam, while them with avolatile solvent and finally treat- 7 keeping the coffee beans in violent motion,

substantially as described.

5. The herein described improvement in the process for the removal of cafiein from which consists in first treating the greencofiee beans with dry steam in order to loosen the cellular structure, then treating them with gaseous chemicals adapted to liberate the cafi'ein from its salts and. then extracting the cafi ein with a volatile solvent.

6. The herein described improvement in the process for the removal of caflein from green coffee beans, which consists in first trating the green coffee beans with dry steam,

in order to loosen the cellular structure, then treatin them with gaseous chemicals adapted to li erate the caffein from its salts and then extracting the cafiein with a mixture of volatile solvents. I

7. As a new article of manufacture unbrokengreen coffee beans originally containing caffein but freed therefrom and having their remaining natural constituents substantially unimpaired.

In testimony whereof we have set our hands hereunto in presence of two subscribing witnesses.

JOHANN FRIEDRICH MEYER, JR. LUDWIG ROSELIUS.

KARL WIMMER.

Witnesses: A O. DIEDERICH, FR. HorERMANN. 

